The present invention concerns a connecting plug for a medical bipolar coagulation instrument, for example, for a bipolar coagulation pincette or for a bipolar electrode, with two blades separated at the ends by insulating material and joined by an insulating body, the blades exhibiting or forming electrical connectors, especially electrical connecting lugs, beyond the range over which they are joined together and the insulating body surrounding and running between the blades and exhibiting for this purpose longitudinally oriented openings for receiving or insertion of the blades.
DE-PS 2,006,126 discloses a coagulation pincette with a connecting plug of this type, the insulating body being formed as an injection-molded plastic part. The blades, due to the one-piece combination of this coagulation pincette with its connecting plug, need to be held by this insulating body spaced and insulated from each other. Thus, the insulating body simultaneously has a securing function in addition to its insulating function. It is therefore necessary to design this insulating body to be relatively bulky, which is a hindrance in handling especially because the end of the pincette is consequently relatively unwieldy and heavy, which is undesired, for example, in microsurgery. In spite of this bulky design, which is necessary for sufficient mechanical strength, one can not exclude the possibility that the blades will loosen with time due to movement and various thermal stresses occurring especially during sterilization so that the pincette becomes useless.
From DE-PS 30 12 849 a bipolar coagulation pincette with a connecting plug of the type mentioned above is known, in which the blades with the electrical connectors are inserted in two plastic shells and these are then held together by a sheath. Thus, the insulating body mainly has the function of a spacer and insulator while the outer sheath surrounds this insulating body in pressing and stabilizing fashion. The result is a stable joining of the blades which remains unchanged over a longer period of use. In addition, the outer dimensions can be reduced. Accordingly, this solution has become widespread even though it causes high production costs due to the manufacture of individual parts and their assembly. Beyond this, this arrangement is also subject to thermal stressing during sterilization so that different coefficients of expansion together with alternating bending loads during use as a result of opening and closing the pincette can lead to a gradual loosening.
From DE 34 09 061 C1 a bipolar coagulation instrument with a plug of the type mentioned above is known, which corresponds essentially to that provided by DE-PS 30 12 849, the insulating body being divided in two. A seam between the two parts of this insulating bodyxe2x80x94as in the coagulation pincette according to DE-PS 30 12 849xe2x80x94can not be avoided or can only be avoided through mutual gluing so that moisture can penetrate over the course of time.
The problem therefore exists of providing a connecting plug for a bipolar coagulation instrument of the type mentioned above, in which reliable securing of the blades in relation to the insulating body is made possible, a long service life of the joining of the blades is obtained, and production is economical. Nevertheless, seamless insulation of the two blades in the area of the insulating body should be simultaneously possible.
In solving this problem, the above-mentioned connecting plug for a bipolar coagulation instrument or, in the case of a one-piece design of the instrument and the plug, the bipolar coagulation instrument is characterized by the fact that the insulating body and the blades each have holes which are superimposed in the installed position and by the fact that anchoring elements are provided which pass through these holes and penetrate in each case in the installed position at least some of the superimposed holes in the insulating body and the blades. Holes that open toward both sides are provided in the insulating body in which the anchoring elements that penetrate into the holes in the blades fit and are inserted in the installed position.
Thus, one can provide a preferably one-piece insulating body with passageways or openings for insertion of the bladesxe2x80x94in the case of a bipolar coagulation pincette with onepiece connecting plug, the pincette bladesxe2x80x94which is mechanically fixed in the installed position over against the inserted blades or pincette blades by anchoring elements oriented perpendicularly to the direction of pressing or insertion so that, compared to gluing or jamming, mechanically interlocking anchoring results, a continuous and seamless section of the insulating body, however, simultaneously extending between the blades so that no liquid or the like can penetrate in this area and can be brought to boiling or evaporation under the influence of high-frequency energy. Although the anchoring elements are to be inserted in each case from the side into the insulating body and are to be inserted into the holes of the blades, one obtains an arrangement which is relatively simple to manufacture and assemble, but which has the great advantage of a mechanically interlocking joining of the essential parts with each other, namely, the blades and the insulating body. Gluing, which can fail under the thermal stressing of sterilization, can be additionally present, to be sure, but is not necessary for the mutual immobilization against undesired shifts and loosenings.
The two holes in the insulating body can be formed as blind holes or borings and end at a distance from each other. Thus, no liquid can penetrate into the area between these holes; rather, the best possible insulating effect is attained at this point.
The holes can enter the insulating body on opposite sides, align with each other, and run perpendicular to the openings in the blades. This represents a simple arrangement of the holes in the insulating body, which additionally permits the best possible anchoring of the inserted blades.
The holes in the insulating body can open into the openings for the blades or cross these, and the anchoring elements can be located in the installed position with their inwardly lying face flush with the inside of the blades penetrated by them or project beyond the blades. In both alternative cases, the blades are engaged over their entire thickness by the anchoring elements. Since the blades are spaced from each other, the holes and accordingly the anchoring elements can cross the openings and thus also the blades, i.e., even protrude beyond these somewhat on the inside so that the anchoring elements in each case are supported to a certain extent bilaterally in relation to the blades held by them. The mechanical immobilization of the blades within the insulating body is all the more stable and secure in their longitudinal direction.
For the tightest possible arrangement and a strong union, it is appropriate if the anchoring elements have the same cross-section or external contour as the holes and fill these in the installed position over the entire length or depth of the holes and over the thickness of the blades. The anchoring elements then sit practically free of play in the holes so that a correspondingly strong union is produced. At the same time, they close the holes to the entrance of moisture.
The anchoring elements can consist of insulating material, especially of the same material as the insulating body. Thus, they can contact the blades on the inside in the area of their holes without the user needing to avoid contact with the two anchoring elements on the outside of the insulating body or the anchoring elements needing to be insulated on the outside. By using the same material for the anchoring elements and the insulating body, different coefficients of expansion are avoided.
The engageable holes in the blades for securing via the anchoring element can in each case be continuous, especially drilled through. To be sure, mechanical immobilization could also occur if the holes in the blades were not continuous so that the anchoring elements could penetrate only a portion of the thickness of the blades. However, a borehole is more easily produced and the mechanical strength of the joint using the anchoring elements is better if the elements penetrate the entire thickness of the blades or even jut out beyond the blade surface.
The end walls of the anchoring elements facing each other can be spaced from each other in the installed position. This spacing corresponds approximately to the distance which the blind holes in the insulating body have from each other so that a continuous layer of insulating-body insulating material remains in this area, in which, thus, no liquid can enter which unintentionally could be heated up by high-frequency energy under certain circumstances.
For good insulation, it is appropriate and advantageous here if the space between the end walls of the anchoring elements is at least partly and especially completely filled in by the material of the insulating body.
The anchoring elements can be fixed via frictional interlocking and jamming in the receiving holes and, if necessary, can even catch upon insertion into their holes through appropriate profiling. To be sure, this complicates production and assembly and is, under certain circumstances, not even an absolute guaranty against gradual loosening due to thermal and mechanical stressing and movement. It can therefore be expedient to secure (especially glue, heat-seal, or screw) the anchoring elements in the holes or borings receiving them. This has the additional advantage that the sealing against penetration of moisture or liquid is further improved.
Here, a further embodiment can provide that the anchoring elements have a cross-sectional reduction next to the blades, especially a groove running entirely or partially around their periphery for receiving primarily hardening synthetic resin or adhesive. The anchoring elements thus become fixed by this adhesive following its hardening.
The mutual joining of anchoring elements, blades, and the insulating body can be further improved through the fact that the openings for insertion of the blades in the insulating body are, compared to the blade dimensions, enlarged or expanded (possibly conically expanded) on at least one side especially against the insertion direction of the blades. The holes for the anchoring elements are positioned running perpendicular to these openings in this expanded area or at the transition from the expanded to the nonexpanded area. This not only facilitates the introduction or insertion of the blades into the openings in the insulating body and gives the blades better freedom of movement at their point of exit from the insulating body in the direction toward the working ends, but additionally permits the glue provided in the area of the anchoring elements also to enter at least into portions of the openings and, in combination especially with the adhesive located in a groove of the involved anchoring element and directly bonded thereto, improves the form-interlockingjoint to keep the anchoring element from being removed or falling out. For this purpose, it is useful if the expanded area of the openings extends to the anchoring elements and the part of the elements exhibiting a cross-sectional reduction.
The openings in the insulating body, on the one hand, and the holes in the blades, on the other, are appropriately of equal size, have identical contours, and are arranged congruently in the installed position and penetrated by the anchoring elements especially in congruent fashion over their entire cross-section. This produces a stable, positive, frictional joint which excludes loosening, can withstand high thermal stressing, and, however, simultaneously has a good insulating effect and can prevent the penetration of liquid between the insulated blades so that no undesired heating can occur there under the influence of high-frequency energy.
An arrangement further simplified with respect to fabrication can consist in the fact that the openings in the insulating body run or open into each other while the anchoring elements are particularly joined together as one piece into a continuous anchoring element. This permits combining the advantages of good mutual mechanical attachment with simplification of manufacture because a continuous hole for one or two anchoring elements is simpler to produce than two blind holes. With good tight filling of the holes by the anchoring element and possibly additional gluing, one nevertheless also obtains satisfactory insulation and sealing.
The insulating body can have a larger cross-section or diameter in the area of the holes for the anchoring element(s) than in the neighboring region of this insulating body extending in the direction of the electrical connectors, and this area of larger cross-section can serve as a stop for a plug mountable on the electrical connectors. Thus, one obtains an additional function for the insulating body because it can guide the plug and produces a specific insertion depth of the terminals to be joined together. The user only needs to insert the plug up to this stop in order to produce a reliable electrical connection. Thus, one also obtains a control for this electrical plug-type connection.
Above all upon combination of individual or several of the above-described features and measures, one obtains a connecting plug for a bipolar coagulation instrument, in particular, joined as one piece with the latter, for example, for a coagulation pincette in which the danger of premature loosening and thus sliding out of one or both blades (in the case of the coagulation pincette, the pincette blades) from the insulating body is avoided by an additional mechanical safety mechanism. Through additional gluing, any remaining seams or small openings can be closed, and the anchoring elements designed as cross pins can be immobilized and secured. At the same time, one attains a situation where no liquid can penetrate into the insulating body or the compound unit formed by it.